TruckMonkey

I have a '98 F250 4.6 L original. Somehow I cracked the block and I picked up a used 4.6 from a '99 F250. I noticed it has slight differences but it still seemed compatible. I got the old engine out and the new in. I have two wiring connectors that I can't find a home for.

The big problem is this: The engine will turn, but VERY sluggishly, as if it is fighting compression and will not start. What can it possibly be? I can't see how a wiring mis-hap would cause it to be bound down. It should spin freely, even if it doesn't fire. Any help is appreciated.

rtg143

Have you tried to turn it over by hand? See if it turns the same as the old one. That will rule out an engine problem. Some times if an engine sets for awhile in damp areas, (East coast) they can get rust on the cylinger walls if they were left out with no protection. If you know the history of the replacement engine that can rule that out. Get some pictures of the connectors and maybe we can help there.